I. Field of the Invention
This invention relates to a direct contact water heating system and is of the type used primarily for industrial and commercial applications for fuel efficiently producing high volumes of hot water.
II. Background of the Invention
In a direct contact water heating system fuel is burned to produce a flame and hot gas products of combustion that are contacted directly with water to be heated to thereby achieve maximum transfer of heat of combustion to the water, resulting in extremely high efficiencies. An advantage of the direct contact water heating systems, in addition to high efficiency is that sterilization of the heated water is obtained. That is, a higher percentage of any entrained bacteria is killed by the direct contact of water with the gaseous products of combustion compared to other hot water heating systems wherein a membrane, whether of metal or some other material, separates the source of heat from the water being heated.
U.S. Pat. No. 4,773,390 issued Sep. 22, 1987 and entitled "Demand Hot Water System" and U.S. patent application No. 08/763,162 filed Dec. 10, 1996 and entitled "Hot Water Heating System" are good background sources for this disclosure. U.S. Pat. No. 4,773,390 describes a high efficiency hot water system in which fuel is combusted with the products of combustion contacting water to be heated within a water tower. The patent application discloses improvements, refinements and innovations to the basic concept of the demand hot water system described and illustrated in the patent.
For additional background information relating to hot water heating systems of the type commonly employed in industrial and commercial applications, reference may be had to the following previously issued United States patents:
______________________________________ U.S. PAT. NO. INVENTOR TITAL ______________________________________ 1820755 McMullen Method of Preparing Liquid Fuel For Burning 2218281 De Ridder et al Method For Cooling Flue Gas 2975594 Eastman Generation of Power From Ash-Forming Hydrocarbons 3183864 Stengel Method and System For Operating A Furnace 3741712 Delatronchette Supply System For A Light Hydrocarbon-Water Emulsion Burner 3749318 Cottell Combustion Method and Apparatus Burning An Intimate Emulsion Of Fuel and Water 3797992 Straitz, III Crude Oil Burner 3814567 Zink et al Smokeless Flare Using Liquid Water Particles 3860384 Vulliet et al Method To Control Nox Formation In Fossil-Fueled Boiler Furnaces 4089633 Barghout et al Combustion Vapor Generator 4089639 Reed et al Fuel-Water Vapor Premix For Low Nox Burning 4368035 McCartny et al Method and Apparatus For Heating Aggregate 4394118 Martin Method and Arrangement For Reducing Nox Emissions From Furnaces 4406610 Duijvestijn Process and Burner For The Partial Combustion Of A Liquid or Gaseous Fuel 4538981 Ventrurini Combustion Catalyzing System For Commercial Grade Fuels 4634370 Chesters Flare 4771762 Bridegum Water Heater For Recreational Vehicle 4773390 Watts Demand Hot Water System 5022379 Wilson, Jr. Coaxial Dual Primary Heat Exchanger 5249957 Hirata Emulsion Producing Apparatus and Its Combustion System 5337728 Maruyama Liquid Heating Apparatus 5341797 Maruyama Liquid Heating Apparatus 5666944 Ferguson Water Heating Apparatus With Passive Flue Gas Recirculation ______________________________________
In addition to these previously issued patents, the references cited against them that are not specifically enumerated hereinabove also form good background material relating to the subject of this invention.